Netting of commercial fruit trees - guidelines to protect wildlife
These guidelines have been developed to help commercial fruit growers to construct nets that:
- protect fruit trees from damage from wildlife such as flying-foxes and some bird species
- protect fruit trees from other risks such as wind and hail
- minimise injury to native wildlife.
The guidelines advocate full exclusion netting as the only reliable method of achieving the above objectives. They have been prepared by OEH, NSW Agriculture and the NSW Flying-Fox Consultative Committee.
Legal protection of flying-foxes
Flying foxes are protected by various pieces of legislation:
Under NSW legislation, it is an offence to harm a protected or threatened species. You must not harm species by netting, trapping, capturing, injuring or killing them. If you put up a netting structure, you must make sure that the structure does not trap or injure protected and threatened animals. You could be prosecuted if you fail to do this.
Unacceptable netting structures
Any netting structure that may lead to harm of native animals is unacceptable and should not be used. For example, throw-over netting, which is hung loosely over trees or support structures, often entangles flying-foxes and other animals, leading to injury or death.
Acceptable netting structures
Any netting structure must be properly tensioned and held away from trees to minimise the risk of entangling wildlife. Two recommended types of structure are full exclusion netting and tunnel netting.
Full exclusion netting
This is the preferred option. It is suitable for larger orchards with close tree and row spacings. It consists of a flat canopy held permanently by a rigid structure of poles and tensioned cables over the entire orchard.
Full exclusion netting has numerous benefits. It can:
- keep out animals such as fruit-eating birds, flying-foxes, fruit-piercing moths, possums, rodents, hares and wallabies which may cause damage to crops (depending on the mesh size)
- protect crops from wind and hail damage
- provide fruit trees with a superior microclimate, depending on crop and location
- help contain spray drift
- offer an environmentally sound practice
- cost relatively little to maintain. Good quality nets can last up to 10-12 years and netting frames up to 40 years. Maintenance will be required to repair torn netting and retention structures after hail or storms.
Nests may be difficult to erect in some topography. Orchardists in the Sydney Basin and Central Coast Regionas can apply for netting subsidies.
Tunnel netting - using hoop frame and coat hanger structures - is suitable for smaller orchards with short, closely lined trees and wide row spacings. It consists of a series of light frames, connected by wires at intervals to support the net and hold it away from the tree.
Tunnel nets are placed over the netting structure prior to fruiting, and are removed after harvest. The net must be pegged to the ground every few metres, or fastened to a wire runner on the ground on either side of the trees. This will tension the netting, stopping the entry of flying-foxes and birds and preventing their capture.
Although initially less expensive, cumulative costs are significant, as the netting must be erected during harvest time, and then removed and carefully stored at the end of each season to avoid damage. Tunnel structures wear quickly and must be replaced more often than full exclusion netting. They may also interfere with spraying, slashing and pruning.
Because tunnel netting only covers crops for small periods, changes in orchard microclimate are minimal and pollination is not affected.
Knitted and knotted netting are both recommended, though knitted netting is the preferred option. The netting mesh size should be based on the animals to be excluded, and the environmental conditions. To exclude flying-foxes and larger birds, you must use a maximum mesh size of 40 mm. To protect crops from hail and fruit-piercing moths, a mesh size of 10 mm or less is required.
Note that smaller mesh size is often more expensive and requires a sturdier supportive structure. For detailed information on netting materials and construction techniques, see Rigden and Chapman, 'To net or not to net: flying fox control in orchards through netting protection', which is published by the Queensland Department of Primary Industries.
Dealing with injured wildlife
When wildlife has become entangled in netting or injured in some way, you should:
Take care when handling dead or injured animals. In particular, avoid handling injured or trapped flying-foxes. These animals can carry diseases that may be transmissible to humans, including bat lyssavirus. They should be buried deeper than 15 cm underground.
Always wear gloves and seek assistance, where possible, from experienced individuals with the appropriate skills and current vaccinations.
If bitten or scratched by a flying-fox, wash the wound carefully with soap and water and contact your local doctor immediately.
More information and useful resources
Some of these references are available from the OEH library.
- Australian Bat Society 1999, Living With bats.
- Department of Primary Industries, Queensland 1988, Agrilink - Low chill stonefruit information kit.
- Eby P 1995, The biology and management of flying-foxes in NSW.
- Eby P 1995, Changes in management practices for flying-foxes in eastern Australia, the sixth conference of the Australian Council on tree and Nut Crops Inc. Lismore, 1995.
- Gough JD 1992, Drift nets of the Northern Rivers, proceedings of the Fruit Crop Protection Seminar, NPWS Hornsby, 1992, pp 14-17.
- Hall J 1992, Netting orchards against flying-foxes, birds and hail, proceedings of the Fruit Crop Protection Seminar, NPWS Hornsby, 1992, pp 24-28.
- Hall LS 1986, Identification, distribution and taxonomy of Australian flying-foxes (Chiroptera:Pteropodidae), proceedings of the First National Flying-fox Symposium Department of Anatomy, University of Queensland 1986, pp 75-79.
- Kur-ring-gai Bat Conservation Society 2002, Backyard fruit tree protection.
- NSW National Parks and Wildlife Service 2002, Policy and procedures for the mitigation of commercial crop damage by flying-foxes for Implementation in 2002/03, NPWS, Hurstville NSW.
- Reilly T and Slack J 1992, Cost and returns of netting low-chill stonefruit orchards, proceedings of the Fruit Crop Protection Seminar, NPWS Hornsby, 1992, pp 33-37.
- Rigden P, Page J and Chapman J 2000, To net or not to net, flying fox control in orchards through netting protection, Department of Primary Industries, Queensland.
- Rigden P and Chapman J 2002, To net or not to net: flying fox control in orchards through netting protection (2nd edition). Department of Primary Industries, Queensland.
- Scientific Advisory Committee 2001, Final determination to list the grey-headed flying-fox, Pteropus poliocephalus Temminck 1825, as a vulnerable species, Department of Natural Resources and Environment, Melbourne.
- Slack J 1990, Flying fox damage in low-chill stonefruit orchards, proceedings of the flying fox workshop, NSW Agriculture and Fisheries, Wollongbar Agricultural Institute, Alstonville, 1990 pp 56-60.
- Snell J 1992, The next step, proceedings of the Fruit Crop Protection Seminar, NPWS Hornsby, 1992, pp 29-32.
- Spence J 1992, The case for netting orchards, proceedings of the Fruit Crop Protection Seminar, NPWS Hornsby, 1992, pp 18-19.
- Tidemann CR and Nelson JE, Flying foxes (Chiroptera: Pteropodidae) and bananas: some interactions, proceedings of the First National Flying Fox Symposium Department of Anatomy, University of Queensland 1986, pp 133-136.
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Page last updated: 05 March 2014